AFD Out of Atlanta Georgia, Very Cold with STJ?

[Wnghs2007]

FFC says that the models are showing the Main Trough Retrograding and allowing the STJ to reactivate again, WITH the Cold air in place. MAYBE we could see the snow and Icestorm threat increase!! AND ALSO, BRING ON THE COATS!!!! ITS GONNA BE COLD!!!!

FXUS62 KFFC 141908
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
205 PM EST TUE DEC 14 2004

.SYNOPSIS...
PATTERN CHANGE ADVERTISED LAST WEEK IS NOW IN FULL SWING. THIS
PATTERN WILL LAST THE REST OF THIS MONTH AND WILL STRENGTHEN. THIS
MEANS BLASTS OF ARCTIC AIR. EACH WILL BE AS STRONG OR STRONGER THAN
THE LAST. THERE WILL ALSO BE SOME FLURRIES OR LIGHT SNOW SHOWERS IN
THE FAR NORTH WITH EACH SYSTEM. TELECONNECTIONS OF RIDGE DEVELOPING
NEAR 40/50N AND 130W SUPPORTS TROUGH IN EASTERN US TO RETROGRADE
SLIGHTLY TO NEAR MS RIVER NEXT 7 TO 14 DAYS. THIS MAY ALLOW GRADUAL
TREND FROM MUCH BELOW NORMAL TEMPS AND DRY TO MUCH BELOW NORMAL
TEMPS AND A LITTLE WETTER PATTERN.

.SHORT TERM...
SOME FLURRIES WILL LINGER THROUGH EARLY EVENING IN THE FAR NE GA
MOUNTAINS. NO ACCUMULATIONS WILL BE MENTIONED. HOWEVER...COLD AIR
ADVECTION WILL BE WEAKENING THIS EVENING WHICH SHOULD ALLOW SKIES TO
BECOME CLEAR ALL AREAS. AS HIGH PRESSURE SETTLES INTO THE
REGION...WIND WILL BEGIN TO DIMINISH. THIS WILL SET THE STAGE FOR
THE FIRST WIDESPREAD HARD FREEZE THAT WE DISCUSSED LAST WEEK. WILL
MAINTAIN FREEZE WARNING ONE MORE NIGHT. BASED ON LOW LEVEL
THICKNESSES (1000/850)...LIGHTER WINDS...AND SURFACE DEWPOINTS IN
THE TEENS...SEEMS LIKE 18 TO 25 ACROSS NORTH TO MIDDLE GA.

LOOKS LIKE MOSTLY CLEAR CONDITIONS WED INTO THU WITH WARM AIR
ADVECTION ALLOWING TEMPS TO WARM UP...BUT STILL WILL BE BELOW
NORMAL.

A WEAK DISTURBANCE WILL PASS THE AREA FRIDAY WITH SOME CLOUDS...BUT
NO PRECIP AS PE VALUES BELOW 0.4 INCHES.

.LONG TERM...
POLAR AIR WILL SURGE BACK INTO GEORGIA SUNDAY INTO MONDAY AS PNA
PATTERN STRENGTHENS AND PATTERN BUCKLES. CONFIDENCE IS FAIRLY HIGH
AS MODELS TEND TO MISS COLD AIR BLOBS IN AMPLIFYING PNA PATTERN.
GFS/ECWMF/UKMET/CANADIAN ALL TRENDING COLDER AND STRONGER WITH
PATTERN. BASED ON BLEND OF 1000/850 THICKNESSES FROM MODELS...SEE NO
REASON NOT TO HIT THIS FAIRLY HARD AND GO WITH TEMPS NO WARMER THAN
WITH THIS CURRENT SURGE OF COLD AIR. STRONG CAA LATE SUN INTO MON
WILL MEAN MORE LIGHT SNOW SHOWERS/FLURRIES IN FAR NORTH WITH WINDY
CONDITIONS.

LOOKS LIKE TREND IS FOR EVEN COLDER AIR BEYOND 7 DAY FORECAST WITH
INCREASE CHANCE FOR PRECIPITATION AS SOME RETROGRESSION WILL OCCUR
ALLOWING SOUTHERN STREAM TO MIX IN WITH NORTHERN STREAM POLAR AIR.
&&

.PRELIMINARY POINT TEMPS/POPS...
ATLANTA 24 46 28 53 / 00 00 00 00
ATHENS 23 46 24 54 / 00 00 00 00
GAINESVILLE 22 45 26 51 / 00 00 00 00
ROME 20 46 19 54 / 00 00 00 00
COLUMBUS 24 52 26 56 / 00 00 00 00
MACON 23 52 23 56 / 00 00 00 00
&&

.FFC WATCHES/WARNINGS/ADVISORIES...HARD FREEZE WARNING ALL AREAS
TONIGHT.
&&

$$

NOEL

TIME TO PAR....TY!!!

[Janie34]

LOOKS LIKE TREND IS FOR EVEN COLDER AIR BEYOND 7 DAY FORECAST WITH
INCREASE CHANCE FOR PRECIPITATION AS SOME RETROGRESSION WILL OCCUR
ALLOWING SOUTHERN STREAM TO MIX IN WITH NORTHERN STREAM POLAR AIR.

Uh-oh!

That's the key ingredient: The southern branch has to get involved in the mix. It's just about the only way I'd get anything, for example.

[dvdweatherwizard]

Ah, I see that Noel wrote that discussion. He is actually their service hydrologist, but I think he writes the best discussions out of the bunch there. Also good from FFC in terms of the AFD is forecaster "RAB", and occasionally whoever has Forecaster ID #24 is interesting. Beyond them, typically what I've found is you'll get one short paragraph, although there are of course exceptions.

[Janie34]

AS WE GET INTO SUNDAY NIGHT AND MONDAY...THE MOISTURE MOVES EASTWARD
AND VERY COLD AIR MOVES IN. THE CURRENT GFS SOLUTION INDICATES 850
MB TEMPS OF -24C AT 06Z MON. -24C AT 850 MB WOULD EQUATE TO A SUPER
ARCTIC AIR MASS. HOWEVER...MODELS HAVE YET TO CONVERGE ON ANY COLD
OUTBREAK OF SUCH A MAGNITUDE AT THIS TIME. IN FACT...THIS IS ONLY 1
MODEL RUN AND THE RIDGING PATTERN OVER THE WESTERN U.S. AND EASTERN
PACIFIC WOULD NEED TO AMPLIFY MORE TO ADD CREDENCE TO ANY MAJOR
SUPER ARCTIC OUTBREAK. AT THIS TIME...WILL TREND ONLY SLIGHTLY BELOW
EXTENDED GUIDANCE AND AWAIT FUTURE MODEL RUNS. ALL MODLES
HOWEVER...ARE LEANING TOWARD BELOW NORMAL TEMPERATURES FOR NEXT WEEK
AS MODIFIED ARCTIC AIR...AT A MINIMUM...SETTLES IN ACROSS THE SOUTH.

NWS-Nashville knows something is up as well. I think the forecaster is talking about the weekend front and not what might be happening around Christmas. Still, it is interesting that a number of NWS offices are really starting to pay attention now.

I might be showing my ignorance here, but what are the criteria for a "super" arctic outbreak?

[dvdweatherwizard]

AS WE GET INTO SUNDAY NIGHT AND MONDAY...THE MOISTURE MOVES EASTWARD
AND VERY COLD AIR MOVES IN. THE CURRENT GFS SOLUTION INDICATES 850
MB TEMPS OF -24C AT 06Z MON. -24C AT 850 MB WOULD EQUATE TO A SUPER
ARCTIC AIR MASS. HOWEVER...MODELS HAVE YET TO CONVERGE ON ANY COLD
OUTBREAK OF SUCH A MAGNITUDE AT THIS TIME. IN FACT...THIS IS ONLY 1
MODEL RUN AND THE RIDGING PATTERN OVER THE WESTERN U.S. AND EASTERN
PACIFIC WOULD NEED TO AMPLIFY MORE TO ADD CREDENCE TO ANY MAJOR
SUPER ARCTIC OUTBREAK. AT THIS TIME...WILL TREND ONLY SLIGHTLY BELOW
EXTENDED GUIDANCE AND AWAIT FUTURE MODEL RUNS. ALL MODLES
HOWEVER...ARE LEANING TOWARD BELOW NORMAL TEMPERATURES FOR NEXT WEEK
AS MODIFIED ARCTIC AIR...AT A MINIMUM...SETTLES IN ACROSS THE SOUTH.

NWS-Nashville knows something is up as well. I think the forecaster is talking about the weekend front and not what might be happening around Christmas. Still, it is interesting that a number of NWS offices are really starting to pay attention now.

I might be showing my ignorance here, but what are the criteria for a "super" arctic outbreak?

Haha, to my knowledge, there is no set criteria for a "super" arctic outbreak, or at least I have never heard officially of a "super" arctic outbreak before. I think the forecaster might have just been trying to emphasize how cold the model really was. I could be wrong though. If anybody does know of "official" criteria for a "super" arctic outbreak, I'd love to hear what they are as well.

[JenyEliza]

FFC says that the models are showing the Main Trough Retrograding and allowing the STJ to reactivate again, WITH the Cold air in place. MAYBE we could see the snow and Icestorm threat increase!! AND ALSO, BRING ON THE COATS!!!! ITS GONNA BE COLD!!!!

NO ICE STORM!! SNOW ONLY. We are surrounded by large, large pines that DON'T LIKE ICE. In January 2000, they dropped their tops on our roof, demolishing it at 3:00 am--while we were sleeping. We were lucky not to be injured, or worse---killed.

NO ICE. SNOW ONLY, please.

[Pileus]

The so-called I-85 winter storms as we call them here in Charlotte area.
Is the southern branch mainly responsible for the development of these
storms that move up the 85 corridor this way? Thanks

[Brent]

FFC says that the models are showing the Main Trough Retrograding and allowing the STJ to reactivate again, WITH the Cold air in place. MAYBE we could see the snow and Icestorm threat increase!! AND ALSO, BRING ON THE COATS!!!! ITS GONNA BE COLD!!!!

NO ICE STORM!! SNOW ONLY. We are surrounded by large, large pines that DON'T LIKE ICE. In January 2000, they dropped their tops on our roof, demolishing it at 3:00 am--while we were sleeping. We were lucky not to be injured, or worse---killed.

NO ICE. SNOW ONLY, please.

I agree. Ice sucks. We're way overdue for one here, as we are for a big snow.

[Janie34]

Haha, to my knowledge, there is no set criteria for a "super" arctic outbreak, or at least I have never heard officially of a "super" arctic outbreak before. I think the forecaster might have just been trying to emphasize how cold the model really was. I could be wrong though. If anybody does know of "official" criteria for a "super" arctic outbreak, I'd love to hear what they are as well.

LOL! I thought that looked strange!

I've forgotten how to extrapolate surface temperatures from the 850 mb level. It's time for finals and, right on cue, my brain has turned to mush. I do know that a translation from -24C at the 850 to a surface temp has got to be cold.


OTOH, it is the GFS. Handle With Care. Someone could bust a forecast like that. Heh.